Although wireless devices have become common in a variety of applications, certain applications have yet been unable to fully benefit from wireless technology. For example, certain wireless devices provide on/off switching, such as remote key access and locking devices for automobiles and automated garage door openers. Other wireless devices provide personal communication, such as cellular telephones. Further wireless devices provide for the use of wireless keyboards, monitors and printers in computer systems.
One area that has not yet fully benefited from the use of wireless devices is medical applications within an emergency care providing environment, such as in a hospital emergency room or inside an ambulance. Although wireless devices are used in emergency medical environments, such devices typically involve receivers that are dedicated to receive data from a specific transmitter device. In an emergency medical environment, it is desirable to very quickly begin monitoring a patient for a variety of continuous signals, such as pulse, electrocardiogram signals etc. Equipment for providing such monitoring must be attached to the patient and connected to monitoring equipment. This requires time, which is critical, and may obstruct access to the patient due to the presence of wires leading to the monitoring equipment.
For example, U.S. Pat. No. 5,685,314 discloses a patient monitoring system including an auxiliary docking station that may be connected with a monitor system via a single connector that provides for multiple simultaneous connections. ('314 patent, col. 3, lines 4–14). Although such a system may save time, the presence of the wires may provide an obstruction in some situations.
A wireless optical patient monitoring apparatus is disclosed in U.S. Pat. No. 5,865,733 that includes optical sources that attach to a patient and an optical receiver including photodetectors for receiving fetal monitoring signals from the patient. The optical sensors are disclosed to be hard-wire connected to a fetal monitoring console that includes a chart recorder. The '733 patent discloses that the use of optical transmission is preferred over radio frequency transmission where multiple patients may be monitored in the same hospital ('733 patent, col. 1, lines 46–59).
A medical diagnostic ultrasound imaging system is disclosed in U.S. Pat. No. 6,238,344 that includes wireless communication via infrared signals to a controlled peripheral, and states that the controlled peripheral may be, inter alia, a VCR, a DVD player/recorder, a printer, a multi-image camera, a strip-chart recorder, a computer or a robot. ('344 patent, col. 2, lines 38–43). The '344 patent discloses that individual commands be transmitted via the wireless channel and that the peripheral devices (preferably a VCR) be programmed to respond to the commands in a specific fashion. ('344 patent, col. 3, lines 2–16 and col. 4, lines 9–10).
There is a need for a wireless device that is capable of receiving continuous data in real time. Although certain wireless communication systems exist in certain non-medical applications, such devices have not been suitable for use in transmitting continuous data in real time as required, for example for chart recorders in medical applications.
A remote data collection and monitoring system for a distribution line is disclosed in U.S. Pat. No. 5,381,136 that includes a plurality of remote data collecting units that provides operation data to the central controller via a radio frequency transmission system when prompted by the central controller. Although each data collecting unit may include a chart recorder, the data that is sent via radio frequency transmission to the central controller when requested includes alarm related data only.
U.S. Pat. No. 6,389,457 discloses a wireless data transmission system in which each remote user unit is able to select certain data from a central host system and the selected data is then pushed to the remote user unit. The pushed data is repackaged and sent via electronic mail (email) responsive to the triggering event of the user selecting the data.
There is a need, therefore, for a wireless chart recorder that is able to print continuous streaming data in real time. Three is further a need for a wireless chart recorder that is able to select from a variety of input signals, a particular input signal that is recorded in a continuous fashion.